FIRE DETECTION DEVICE

PURPOSE:To speedily discriminate which of a heat detection part or a smoke detection part acts and to prevent the delay of an alarm and wrong information. CONSTITUTION:A detection circuit 2 where a terminal resistance part 3, the heat detection parts 4... whose impedance changes by the detection of heat, and the smoke detection parts 5... whose impedance changes by the detection of smoke are connected in parallel between two connection lines 6 and 7 is provided. First voltage VH is given to the detection circuit 2 at regular time, and second voltage VL which does not operate the smoke detection parts 5... based on the detection operations of the heat detection parts 4... and (or) the smoke detection parts 5... is given to the circuit. Thus, the detection part 4 or 5 which has acted by detecting heat or smoke, is discriminated based on the level of current Ir flowing in the detection circuit 2 at the time of giving second voltage VL.